problem w/ multiple jcombobox

I've been working with a project that requires me to use mutiple jcombobox. I did try to relate three jcombobox but failed to show all necesarry drop-down lists.
in one of my combobox I have lists of Banks (Bank1, Bank2), the other one is the list of all branches in a specific Bank that has been selected (Bank1(branch1-1, branch1-2), Bank2(branch2-1, branch2-2)) and the last one are the account # for all specific branches that has been selected. each branches has a multiple accounts. I have no problem working with 2 comboboxes, all branches are shown for a specific Bank that has been selected, but, when I added the third combobox which is the account #, only one branch is being queried from my db. ex. if I select Bank1 only "branch1" will be on the list, and if Bank2 only branch2-1 will be on the list also, but account # for that specific branches are on the drop-down lists.

as ive said, if I use 2 jComboboxes all branches for a specific selected Bank will be in the drop-down list but when I added the 3rd jCombobox(3) for accountNO only the first (one) branch will be on the jCombobox(2) drop-down list.

can you show me a simple chained 3 jcomboboxes w/ db connection? im really stuck with what im doing, only the first query is being shown in my 2nd combobox when the 3rd combobox are filled with data from db. thank you very much for your response.